1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) 2019 Arm Ltd.
3 *
4 * Based on msm_gem_freedreno.c:
5 * Copyright (C) 2016 Red Hat
6 * Author: Rob Clark <robdclark@gmail.com>
7 */
8
9#include <linux/list.h>
10
11#include <drm/drm_device.h>
12#include <drm/drm_gem_shmem_helper.h>
13
14#include "panfrost_device.h"
15#include "panfrost_gem.h"
16#include "panfrost_mmu.h"
17
18static unsigned long
19panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
20{
21 struct panfrost_device *pfdev = shrinker->private_data;
22 struct drm_gem_shmem_object *shmem;
23 unsigned long count = 0;
24
25 if (!mutex_trylock(lock: &pfdev->shrinker_lock))
26 return 0;
27
28 list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {
29 if (drm_gem_shmem_is_purgeable(shmem))
30 count += shmem->base.size >> PAGE_SHIFT;
31 }
32
33 mutex_unlock(lock: &pfdev->shrinker_lock);
34
35 return count;
36}
37
38static bool panfrost_gem_purge(struct drm_gem_object *obj)
39{
40 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
41 struct panfrost_gem_object *bo = to_panfrost_bo(obj);
42 bool ret = false;
43
44 if (atomic_read(v: &bo->gpu_usecount))
45 return false;
46
47 if (!mutex_trylock(lock: &bo->mappings.lock))
48 return false;
49
50 if (!dma_resv_trylock(obj: shmem->base.resv))
51 goto unlock_mappings;
52
53 panfrost_gem_teardown_mappings_locked(bo);
54 drm_gem_shmem_purge(shmem: &bo->base);
55 ret = true;
56
57 dma_resv_unlock(obj: shmem->base.resv);
58
59unlock_mappings:
60 mutex_unlock(lock: &bo->mappings.lock);
61 return ret;
62}
63
64static unsigned long
65panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
66{
67 struct panfrost_device *pfdev = shrinker->private_data;
68 struct drm_gem_shmem_object *shmem, *tmp;
69 unsigned long freed = 0;
70
71 if (!mutex_trylock(lock: &pfdev->shrinker_lock))
72 return SHRINK_STOP;
73
74 list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
75 if (freed >= sc->nr_to_scan)
76 break;
77 if (drm_gem_shmem_is_purgeable(shmem) &&
78 panfrost_gem_purge(obj: &shmem->base)) {
79 freed += shmem->base.size >> PAGE_SHIFT;
80 list_del_init(entry: &shmem->madv_list);
81 }
82 }
83
84 mutex_unlock(lock: &pfdev->shrinker_lock);
85
86 if (freed > 0)
87 pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
88
89 return freed;
90}
91
92/**
93 * panfrost_gem_shrinker_init - Initialize panfrost shrinker
94 * @dev: DRM device
95 *
96 * This function registers and sets up the panfrost shrinker.
97 */
98int panfrost_gem_shrinker_init(struct drm_device *dev)
99{
100 struct panfrost_device *pfdev = dev->dev_private;
101
102 pfdev->shrinker = shrinker_alloc(flags: 0, fmt: "drm-panfrost");
103 if (!pfdev->shrinker)
104 return -ENOMEM;
105
106 pfdev->shrinker->count_objects = panfrost_gem_shrinker_count;
107 pfdev->shrinker->scan_objects = panfrost_gem_shrinker_scan;
108 pfdev->shrinker->private_data = pfdev;
109
110 shrinker_register(shrinker: pfdev->shrinker);
111
112 return 0;
113}
114
115/**
116 * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
117 * @dev: DRM device
118 *
119 * This function unregisters the panfrost shrinker.
120 */
121void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
122{
123 struct panfrost_device *pfdev = dev->dev_private;
124
125 if (pfdev->shrinker)
126 shrinker_free(shrinker: pfdev->shrinker);
127}
128

source code of linux/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c